Fire-detecting device is used in an automatic fire alarm system, to probe on spot and raise an alarm while a fire accident occurs. It plays a role of keeping the surrounding under fire surveillance. In case of fire, the device will transform some fire physical parameters, e.g. temperature, etc. into electrical signals, and then activate the fire alarm controller immediately.
In case of fire, a temperature-sensing glass pillar in a conventional fire-detecting device will crack off, and then its mechanical devices, such as springs and weights etc, will be released, leading to building's louver vents open, building's fire dampers shutting, store's rolling gates being closed and the inlet valves for warehouse of flammable substances being closed completely, and so on.
However, a spring utilized in the existing devices may be worn or deformed permanently so as to impact the mechanical properties of the fire-detecting device. Besides, when the fire-detecting device is deadlocked, it will be very inconvenient to replace the temperature-sensing glass pillar.
Most existing fire-detecting devices utilize fusible alloys as the temperature-sensing element. However, the technology of utilizing fusible alloys in the fire-detecting device will disappear in the future since RoHS restricts the use of such fusible alloys. Meanwhile most existing fire-detecting devices are not provided with failure protection, which means that the assembly inside the device cannot work properly and the detection is failure when its mechanical devices, such as springs and weights etc, are released.